Question

Tìm x biết

     (x-7)^x+11=(x-7)^x+1

Help me ;-)♥

Answer 1

\(\left(x-7\right)^{x+11}=\left(x-7\right)^{x+1}\)

\(\Rightarrow\left(x-7\right)^{x+11}-\left(x-7\right)^{x+1}=0\)

\(\Rightarrow\left(x-7\right)^{x+1}\left[\left(x-7\right)^{10}-1\right]=0\)

\(\Rightarrow\orbr{\begin{cases}\left(x-7\right)^{x+11}=0\\\left(x-7\right)^{10}-1=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x-7=0\\\left(x-7\right)^{10}=1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=7\\x=6or\text{ }x=8\end{cases}}\)